Apparatus and Method for Mounting Flow-Control Devices to Tubular Members

ABSTRACT

A contoured boss for conforming to an outer surface of a tubular member for deployment within a subterranean formation, the contoured boss comprising a valve receiving body having a contoured outer surface that extends radially outward from an outer surface of the tubular member; and passage for receiving a valve, the passage extending through the valve receiving body. A method for facilitating stimulation treatments in completions and a method of centering a tubular member having an outer surface within a borehole are also provided.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional No. 61/810,993, filed Apr. 11, 2013, which is incorporated by reference herein in its' entirety.

FIELD

The present disclosure is directed generally to wellbore flow-controls for hydrocarbon wells, and more particularly to methods and components for mounting wellbore flow-control devices to tubular members.

BACKGROUND

Well drilling operations may utilize a variety of steps during the formation of, completion of, and/or production from a well, such as a hydrocarbon well. Often, these steps are performed sequentially, with dedicated and/or specialized equipment and/or crews being utilized to perform each of the steps. While such a methodology may be effective, it may be costly and/or time-consuming to implement due to equipment costs, labor costs, and/or time required to remove one piece of equipment from the well and deploy another piece of equipment within the well.

As an illustrative example, and subsequent to formation of a wellbore within a subterranean formation, it may be desirable to circulate drilling fluids, such as drilling mud, from the wellbore, to circulate a completion and/or breaker fluid into the subterranean formation, and/or to pump a wiper plug or other sealing device to a terminal depth of the wellbore. These operations typically involve supplying a fluid stream through a fluid conduit and from a surface region to, or proximal to, a terminal depth of the wellbore and may require a substantially fluid-tight seal within the fluid conduit from the top of the wellbore to the terminal depth of the wellbore.

Traditionally, a casing string, or liner, may be located within the wellbore. However, this casing string often includes a plurality of holes, perforations, passages, and/or other fluid conduits along a length thereof. These fluid conduits may be configured to provide for outflow of a stimulant fluid from the casing string into the subterranean formation and/or inflow of a reservoir fluid from the subterranean formation into the casing string. Thus, any fluid that is supplied to the casing string may leak through these fluid conduits to the subterranean formation, thereby decreasing a flow rate at the terminal end of the wellbore. Therefore, an inner string that does not include holes along a length thereof may be run into the casing string to facilitate providing the fluid to the terminal depth of the wellbore. However, insertion and/or subsequent removal of this inner string may significantly increase the cost and/or time required to complete the well drilling operation.

As another illustrative example, it also may be desirable to perform one or more stimulation operations to stimulate the subterranean formation and increase a potential for production of the reservoir fluid therefrom. These stimulation operations may include providing a stimulant fluid to specific, or target, regions of the subterranean formation and may utilize stimulation ports within the casing string to provide the stimulant fluid from the casing conduit to the target region of the subterranean formation.

In an increasing number of extended-reach wells, such as those in excess of 10,000 feet, stimulation treatments, such as hydrochloric acidizing, are required. Often these wells are completed with production liners and swell or other types of openhole packers for reservoir management. As those skilled in the art recognize, stimulating these types of wells, especially the distal portions, is very challenging.

One approach taken includes the installation of inflow control devices (ICDs) or other discrete ports positioned between swell packers, followed by pumping the acid through the ICDs. However, this approach merely injects the acid in the vicinity of the ICDs and may fail to stimulate the formation away from the ICDs. Even if the acid migrates along the annulus, it is important to achieve radial impingement of the acid on the formation for effective stimulation. Also, sizing the ICDs so that they are appropriate for both acid injection and hydrocarbon production is very challenging.

Another approach that has been taken is to pre-drill the liner with holes and then perform the stimulation using coiled tubing with an acid jetting bottom hole assembly (BHA). By moving the coiled tubing during acidizing, essentially the entire production interval can be treated. However, this approach may not be feasible for longer (>20,000 ft.) wells because of the difficulty in running coiled tubing in such wells. Also, coiled tubing typically limits acid pumping rates to <5 bbl/min, where rates as great as 50 bbl/min may be desired for improved performance and reduced job time. In addition, creating the perforations and renting the coiled tubing is expensive.

One proposed solution is to deploy a number of small check valves in the wall of the casing or liner, where the opening pressure of the check valves is adjustable. The check valves at the distal portion of the casing string may have the lowest opening pressure, with the opening pressure of the check valves progressively increasing closer to the proximal part of the liner. In this proposal, the acid may be pumped through the liner and out through the check valves.

One problem associated with incorporating a check valve into the wall of a casing string results from the fact that because the wall thickness of a typical casing (e.g., 0.352″ for 24 pounds per foot (ppf) 6⅝″) is less than the length of a typical check valve (0.75″-1.50″ in length). As such, the check valve assembly will protrude from the wall of the casing. This creates concerns for (1) damage to the check valve during casing installation and (2) the check valves creating additional torque and drag impeding installation. In some applications, a 6⅝-inch casing is run inside an 8½-inch hole. That would mean that the annular clearance is only 0.9375 inch, assuming the casing is centralized.

One solution proposed is to position the check valves within a machined cylindrical sleeve. However, problems associated with incorporating check valves into a machined cylindrical sleeve include (1) the expense of manufacturing the sleeve and installing the check valves and (2) the cylindrical sleeve will increase the OD of the casing, which may cause drag problems during installation. For example, assuming that four check valves are used between each 40-ft casing joint, over a 10,000-ft completion interval, about 250 machined cylindrical sleeves would be required for each well, adding significant cost to the completion. Also, the outer diameter (OD) of the assembly may be as high as 7.725 inch, leaving an annular clearance of only 0.3875 inch, creating drag concerns. This small clearance, combined with the debris and/or ledges that typically exist in an open hole and the large number of sleeves required, increases the likelihood that the liner or casing would fail to reach total depth (TD).

Therefore, what is needed are simple, cost-effective methods, systems and apparatus for installing a check valve into the wall of a casing or liner that may reduce torque, drag and/or clearance related issues.

SUMMARY

In one aspect, provided is a contoured boss for conforming to an outer surface of a tubular member for deployment within a subterranean formation. The contoured boss includes a valve receiving body having a contoured outer surface that extends radially outward from an outer surface of the tubular member; and passage for receiving a valve, the passage extending through the valve receiving body.

In some embodiments, the contoured outer surface of the valve receiving body is rounded to reduce surface contact with a borehole surface when the tubular member is positioned within the borehole of the subterranean formation.

In some embodiments, the valve receiving body includes a mounting surface for contacting the outer surface of the tubular member, the mounting surface having an outer periphery.

In some embodiments, the contoured outer surface of the valve receiving body has an outer periphery, the outer periphery of the contoured outer surface located adjacent the outer periphery of the mounting surface of the valve receiving body.

In some embodiments, the valve receiving body includes a welding chamfer, the welding chamfer positioned between the outer periphery of the contoured outer surface and the outer periphery of the mounting surface.

In some embodiments, the contoured outer surface of the valve receiving body is substantially dome-shaped, tear-drop shaped, or rib-shaped.

In some embodiments, the passage of the valve receiving body includes an axial bore having a first portion having a first diameter, the first diameter sufficient to receive the valve from the contoured outer surface, the first portion of the axial bore extending partially through the valve receiving body and terminating at a valve seating shoulder.

In some embodiments, the axial bore of the passage has a second portion having a second diameter, the second diameter less than the first diameter, the second portion of the axial bore initiating at the valve seating shoulder and extending through the mounting surface.

In some embodiments, the axial bore of the passage includes an annular groove for receiving a lock ring for securing the valve within the axial bore.

In some embodiments, a lock ring is provided that is positionable within the annular groove for securing the valve within the axial bore.

In some embodiments, a screen for preventing debris from entering the valve is provided, the screen retained within the axial bore by a lock ring.

In some embodiments, the mounting surface for contacting the outer surface of the tubular member is contoured to substantially mate with the outer surface of the tubular member.

In another aspect, provided is a method for facilitating stimulation treatments in completions. The method includes the steps of (a) drilling a hole through a tubular casing at a first distance along the tubular casing; (b) welding a contoured boss to an outer surface of the tubular casing, the contoured boss including a valve receiving body; a contoured outer surface that extends radially outward from an outer surface of a tubular casing; and a passage for receiving a valve, the passage extending through the valve receiving body and in fluid communication with the hole of the casing; and (c) positioning a valve within the passage.

In some embodiments, the contoured outer surface of the valve receiving body is rounded to reduce surface contact with a borehole surface when the tubular casing is positioned within the borehole of the subterranean formation.

In some embodiments, the valve receiving body includes a mounting surface for contacting the outer surface of the tubular casing, the mounting surface having an outer periphery.

In some embodiments, the contoured outer surface of the valve receiving body has an outer periphery, the outer periphery of the contoured outer surface located adjacent the outer periphery of the mounting surface of the valve receiving body.

In some embodiments, the valve receiving body includes a welding chamfer, the welding chamfer positioned between the outer periphery of the contoured outer surface and the outer periphery of the mounting surface.

In some embodiments, the contoured outer surface of the valve receiving body is substantially dome-shaped, tear-drop shaped, or rib-shaped.

In some embodiments, the passage of the valve receiving body includes an axial bore having a first portion having a first diameter, the first diameter sufficient to receive the valve from the contoured outer surface, the first portion of the axial bore extending partially through the valve receiving body and terminating at a valve seating shoulder.

In some embodiments, the axial bore of the passage has a second portion having a second diameter, the second diameter less than the first diameter, the second portion of the axial bore initiating at the valve seating shoulder and extending through the mounting surface.

In some embodiments, the axial bore of the passage includes an annular groove for receiving a lock ring for securing the valve within the axial bore.

In some embodiments, a lock ring is provided within the annular groove to secure the valve within the axial bore.

In some embodiments, a screen is installed for preventing debris from entering the valve; and a lock ring positioned within the annular groove to secure the valve and screen within the axial bore.

In some embodiments, the method further includes the step of: (d) repeating steps (a)-(c).

In some embodiments, the method further includes the step of: (d) twice repeating steps (a)-(c), wherein three valves are positioned at equal distances about the circumference of the tubular casing to establish a first treatment zone.

In some embodiments, the method further includes the step of: (d) thrice repeating steps (a)-(c), wherein four valves are positioned at equal distances about the circumference of the tubular casing to establish a first treatment zone.

In some embodiments, the method further includes the steps of: (e) drilling a hole through a tubular casing at a second distance along the tubular casing, the second distance greater than the first distance; (f) welding a contoured boss to an outer surface of the tubular casing, the contoured boss comprising a valve receiving body; a contoured outer surface that extends radially outward from an outer surface of the tubular casing; and a passage for receiving the valve, the passage extending through the valve receiving body and in fluid communication with the hole of the casing; and (g) positioning a valve within the axial bore.

In some embodiments, the method further includes the step of: (h) thrice repeating steps (a)-(c), wherein four valves are positioned at equal distances about the circumference of the tubular casing to establish a second treatment zone.

In some embodiments, the valves are check valves.

In some embodiments, the check valves installed at the first distance of the tubular casing require a lower pressure to open than those installed at the second distance of the tubular casing.

In some embodiments, the contoured boss does not restrict tubular flow.

In yet another aspect, provided is a method of centering a tubular member having an outer surface within a borehole. The method includes the steps of: (a) establishing a first distance along the tubular member; and (b) welding a plurality of contoured bosses to the outer surface of the tubular casing at the first distance, each contoured boss including a mounting surface for contacting the outer surface of the tubular casing, the mounting surface having an outer periphery; and a contoured outer surface that extends radially outward from an outer surface of the tubular member, the contoured outer surface rounded to reduce surface contact with the borehole surface when the tubular member is positioned within the borehole; wherein the plurality of contoured bosses are positioned at equal distances about the circumference of the tubular member.

In some embodiments, the method further includes the steps of: (c) establishing a second distance along the tubular member; and (d) welding a plurality of contoured bosses to the outer surface of the tubular casing at the second distance, each contoured boss including a mounting surface for contacting the outer surface of the tubular casing, the mounting surface having an outer periphery; and a contoured outer surface that extends radially outward from an outer surface of the tubular member, the contoured outer surface rounded to reduce surface contact with the borehole surface when the tubular member is positioned within the borehole; wherein the plurality of contoured bosses are positioned at equal distances about the circumference of the tubular member.

In some embodiments, the method further includes the steps of: (e) establishing a third distance along the tubular member; and (f) welding a plurality of contoured bosses to the outer surface of the tubular casing at the third distance, each contoured boss including a mounting surface for contacting the outer surface of the tubular casing, the mounting surface having an outer periphery; and a contoured outer surface that extends radially outward from an outer surface of the tubular member, the contoured outer surface rounded to reduce surface contact with the borehole surface when the tubular member is positioned within the borehole; wherein the plurality of contoured bosses are positioned at equal distances about the circumference of the tubular member.

In some embodiments, each contoured boss includes a valve receiving body having an axial bore for receiving a valve, the axial bore extending through the valve receiving body, the axial bore of the contoured boss in fluid communication with the interior of the tubular member.

In some embodiments, the contoured boss does not restrict tubular flow.

In yet another aspect, provided is a collar or sub for mounting to a tubular member for deployment within a subterranean formation. The collar or sub includes a plurality of contoured bosses integrally formed thereon and spaced about an outer surface thereof, each of the contoured bosses comprising a valve receiving body having a contoured outer surface that extends radially outward from an outer surface of the tubular member; and passage for receiving a valve, the passage extending through the valve receiving body.

In some embodiments, the contoured outer surface of the valve receiving body is rounded to reduce surface contact with a borehole surface when the tubular member is positioned within the borehole of the subterranean formation.

In some embodiments, the contoured outer surface of the valve receiving body is substantially dome-shaped, tear-drop shaped, or rib-shaped.

In some embodiments, the passage of the valve receiving body includes an axial bore having a first portion having a first diameter, the first diameter sufficient to receive the valve from the contoured outer surface, the first portion of the axial bore extending partially through the valve receiving body and terminating at a valve seating shoulder.

In some embodiments, the axial bore of the passage has a second portion having a second diameter, the second diameter less than the first diameter, the second portion of the axial bore initiating at the valve seating shoulder and extending through the mounting surface.

In some embodiments, the axial bore of the passage includes an annular groove for receiving a lock ring for securing the valve within the axial bore.

In some embodiments, the collar or sub further includes a lock ring positionable within the annular groove for securing the valve within the axial bore.

In some embodiments, the collar or sub further includes a screen for preventing debris from entering the valve, the screen retained within the axial bore by the lock ring.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 presents a perspective view of an illustrative, non-exclusive example of a tubular member having a plurality of contoured bosses positioned about the circumference of the tubular member, according to the present disclosure.

FIG. 2 presents a perspective view of an illustrative, non-exclusive example of a contoured boss having a contoured outer surface rounded to reduce surface contact with a borehole surface when affixed to a tubular member, according to the present disclosure.

FIG. 3 presents a perspective view of an illustrative, non-exclusive example of a contoured boss having a mounting surface for contacting an outer surface of a tubular member, the mounting surface contoured to substantially mate with the outer surface of the tubular member, according to the present disclosure.

FIG. 4 presents a side plan view, in partial cutaway, of an illustrative, non-exclusive example of a contoured boss, according to the present disclosure.

FIG. 5 presents a top plan view, in partial cutaway, of an illustrative, non-exclusive example of a contoured boss, according to the present disclosure.

FIG. 6 presents a perspective view of an illustrative, non-exclusive example of a collar or sub having a plurality of contoured bosses positioned about the circumference of the tubular member, according to the present disclosure.

FIG. 7 presents an illustrative, non-exclusive example of a subterranean well that may be utilized with the systems, methods and apparatus of the present disclosure.

DETAILED DESCRIPTION

FIGS. 1-7 provide illustrative, non-exclusive examples of contoured bosses having utility in connection with wellbore flow-control systems and other wellbore-related equipment, methods and systems, according to the present disclosure and/or of systems, apparatus, and/or assemblies that may include, be associated with, be operatively attached to, and/or utilize contoured bosses. In FIGS. 1-7, like numerals denote like, or similar, structures and/or features; and each of the illustrated structures and/or features may not be discussed in detail herein with reference to each of FIGS. 1-7. Similarly, each structure and/or feature may not be explicitly labeled in each of FIGS. 1-7; and any structure and/or feature that is discussed herein with reference to any one of FIGS. 1-7 may be utilized with any other of FIGS. 1-7 without departing from the scope of the present disclosure.

In general, structures and/or features that are, or are likely to be, included in a given embodiment are indicated in solid lines in FIGS. 1-6, while optional structures and/or features are indicated in broken lines. However, a given embodiment is not required to include all structures and/or features that are illustrated in solid lines therein, and any suitable number of such structures and/or features may be omitted from a given embodiment without departing from the scope of the present disclosure.

FIG. 1 presents a perspective view of an illustrative, non-exclusive example of a tubular member section 12 having a plurality of contoured bosses 10 positioned about an outer circumferential surface 14 of tubular member section 12, according to the present disclosure. Referring also to FIGS. 2-5, contoured boss 10 includes a valve receiving body 16 having a contoured outer surface 18 that extends radially outward from an outer surface 14 of tubular member 12 (see FIG. 1). In embodiments where contoured boss 10 is employed to mount a valve 22 therein, a passage 20 for receiving a valve 22 may be provided. In one embodiment, passage 20 may extend axially through valve receiving body 16.

As shown in FIGS. 1-5, the contoured outer surface 18 of valve receiving body 16 may be rounded to reduce surface contact with a borehole surface when a tubular member is positioned within the borehole of the subterranean formation. In some embodiments, contoured outer surface 18 of valve receiving body 16 may be substantially dome-shaped, tear-drop shaped, or rib-shaped.

In some embodiments, the valve receiving body 16 may include a mounting surface 24 for contacting the outer surface 14 of tubular member 12. As shown, contoured outer surface 18 of valve receiving body 16 has an outer periphery 26, outer periphery 26 of contoured outer surface 18 located adjacent outer periphery 28 of mounting surface 24 of valve receiving body 16. In some embodiments, mounting surface 24 for contacting outer surface 14 of tubular member 12 is contoured to substantially mate with outer surface 14 of the tubular member 12.

In some embodiments, valve receiving body 16 includes a welding chamfer 30, the welding chamfer 30 positioned between outer periphery 26 of contoured outer surface 18 and outer periphery 28 of mounting surface 24. As may be appreciated by those skilled in the art, the provision of welding chamfer 30 may aid in the attachment of contoured bosses 10 to a tubular member when such attachment is to be made by welding.

In order to mount a valve 22, in some embodiments, passage 20 of valve receiving body 16 is provided with an axial bore 32 having a first portion 34 having a first diameter 36 (see, in particular FIG. 5). As shown, first diameter 36 is sufficiently sized to receive valve 22 from the contoured outer surface 18 side of contoured boss 10. As best shown in FIG. 4, in some embodiments, first portion 34 of axial bore 32 extends partially through valve receiving body 16 and terminates at or near a valve seating shoulder 38, although other configurations are within the scope of the present disclosure, depending on the type and style of valve to be employed, as those skilled in the art would plainly understand.

In some embodiments, axial bore 32 of passage 20 may be configured to have a second portion 40 having a second diameter 42. As shown, second diameter 42 may be smaller than first diameter 36, with the second portion 40 of axial bore 32 initiating at the valve seating shoulder 38 and extending through the mounting surface 24.

To lock a valve 22 in place within contoured boss 10, in some embodiments, axial bore 32 of passage 20 includes an annular groove 44 for receiving a lock ring (not shown) for securing valve 22 within axial bore 32. Optionally, a screen (not shown) may be provided for preventing debris from entering valve 22. In some embodiments, the screen may be retained within the axial bore 32 by a lock ring (not shown).

Referring now to FIG. 6, another embodiment of the present disclosure is presented. In this form, a collar or sub 100 for mounting to a tubular member (not shown) for deployment within a subterranean formation is provided. As shown, collar or sub 100 includes a plurality of contoured bosses 110, which, in some embodiments, are integrally formed thereon and spaced about outer surface 114. In some embodiments, contoured bosses 110 may be cast as one-piece with collar or sub 100. In other embodiments, collar or sub 100 may be formed by welding contoured bosses 110 to a tubular member, in a manner similar to the embodiments depicted in FIGS. 1-5.

As shown, each of contoured bosses 110 includes a valve receiving body 116 having a contoured outer surface 118 that extends radially outward from an outer surface 114 of collar or sub 100 (see FIG. 1). In embodiments where contoured boss 110 is employed to mount a valve (not shown) therein, a passage 120 for receiving the valve may be provided. In one embodiment, passage 120 may extend axially through valve receiving body 116.

As shown in FIG. 6, the contoured outer surface 118 of valve receiving body 116 may be rounded to reduce surface contact with a borehole surface when collar or sub 100 is positioned within the borehole of the subterranean formation. In some embodiments, contoured outer surface 118 of valve receiving body 116 may be substantially dome-shaped, tear-drop shaped, or rib-shaped.

In order to mount a valve, in some embodiments, passage 120 of valve receiving body 116 is provided with an axial bore 132 having a first portion having a first diameter as shown in the embodiment of FIG. 5. As with the embodiment of FIG. 5, the first diameter is sufficiently sized to receive a valve from the contoured outer surface 118 side of contoured boss 110.

To lock a valve in place within contoured boss 110, in some embodiments, axial bore 132 of passage 120 includes an annular groove (not shown) for receiving a lock ring (not shown) for securing the valve within axial bore 132. Optionally, a screen (not shown) may be provided for preventing debris from entering valve. In some embodiments, the screen may be retained within the axial bore 32 by a lock ring (not shown).

In another aspect, provided is a method for facilitating stimulation treatments in completions. The method includes the steps of (a) drilling a hole through a tubular casing at a first distance along the tubular casing; (b) welding a contoured boss to an outer surface of the tubular casing, the contoured boss including a valve receiving body; a contoured outer surface that extends radially outward from an outer surface of a tubular casing; and a passage for receiving a valve, the passage extending through the valve receiving body and in fluid communication with the hole of the casing; and (c) positioning a valve within the passage.

In some embodiments, the method may further includes the step of repeating steps (a)-(c), to provide a second contoured boss at a first distance along the tubular casing. Similarly, in some embodiments, the method further includes the step of twice repeating steps (a)-(c), wherein three valves are positioned at equal distances about the circumference of the tubular casing to establish a first treatment zone. Likewise, in some embodiments, the method further includes the step of thrice repeating steps (a)-(c), wherein four valves are positioned at equal distances about the circumference of the tubular casing to establish a first treatment zone.

Where desired, such as in the case of providing multiple treatment zones, the method may further include the steps of (e) drilling a hole through a tubular casing at a second distance along the tubular casing, the second distance greater than the first distance; (f) welding a contoured boss to an outer surface of the tubular casing, the contoured boss comprising a valve receiving body; a contoured outer surface that extends radially outward from an outer surface of the tubular casing; and a passage for receiving the valve, the passage extending through the valve receiving body and in fluid communication with the hole of the casing; and (g) positioning a valve within the axial bore.

In some embodiments, the method further includes the step of repeating steps (a)-(c), one or more times, to permit the positioning of additional valves about the circumference of the tubular casing and establish a second treatment zone. As will be described in more detail below, with reference to FIG. 7, in some embodiments, the check valves installed at the first distance of the tubular casing require a lower pressure to open than those installed at the second distance of the tubular casing.

FIG. 7 presents a schematic representation of illustrative, non-exclusive examples of an application of the contoured bosses disclosed herein. As shown, hydrocarbon well 220 includes a wellbore 230 that extends between a surface region 260 and a subterranean formation 268 that is present in a subsurface region 264. Wellbore 230 includes a casing conduit 244 that extends within the wellbore. Casing conduit 244 may be defined by a casing string 240, which also may be referred to herein as a conduit body 240.

As illustrated in dashed lines in FIG. 7, casing conduit 244 may include, or may at least temporarily include, one or more fluid isolation devices (not shown), such as a plug, which may be configured to fluidly isolate an uphole portion of casing conduit 244 from a downhole portion of the casing conduit to facilitate stimulation treatments. In addition, at least a portion of hydrocarbon well 220 may include, contain, be operatively attached to, and/or be utilized with one or more contoured bosses 300, each of which may be provided with valves 322 for flow control, according to the present disclosure.

Valves 322 selectively provide fluid communication between casing conduit 244 and subterranean formation 268 therethrough. Valves 322, enclosed within contoured bosses 300, according to the present disclosure, include and/or define a flow-controlled fluid conduit that is separate, distinct, and/or different from casing conduit 244 and selectively conveys a fluid flow between subterranean formation 268 and casing conduit 244. Depending upon the particular embodiment, the fluid flow may include a fluid outflow from the casing conduit into the subterranean formation, such as in the case of providing a stimulation treatment or a fluid inflow from the subterranean formation into the casing conduit.

Valves 322 may be directional flow-control devices that are adapted, configured, designed, and/or constructed to permit one of fluid outflow or fluid inflow and to resist the other of the fluid outflow or fluid inflow. Illustrative, non-exclusive examples of directional flow-control devices according to the present disclosure include a ball and seat, a check valve, and/or a flapper.

Contoured bosses 300 may be included in, operatively attached to, and/or utilized with any suitable portion of well 220 and/or any suitable component thereof. As an illustrative, non-exclusive example, casing string 240 may include a plurality of casing segments 250, and one or more casing subs 252, which also may be referred to herein as stimulation subs 252 and/or production subs 252, and contoured bosses 300 may be operatively attached to casing segments 250 and/or casing subs 252. As another example, the contoured bosses 300 may be attached to tubing or liner segments 250. The bosses 300 may be mounted on an exterior surface of the tubular conduit, counter-sunk into the wall of the tubular conduit, or positioned into the tubular conduit from the inside of the tubular conduit and at least partially penetrate the wall of the conduit through an exterior surface of the conduit.

As discussed in more detail herein, contoured bosses 300 having valves 322 positioned therein, according to the present disclosure, may be utilized during any suitable operation and/or process that may be performed on and/or in well 220 and/or any suitable component thereof. As an illustrative, non-exclusive example, and subsequent to formation of wellbore 230 and insertion of casing string 240 therein, it may be desirable to circulate, remove, flush, and/or otherwise pump a first fluid from the wellbore, to replace the first fluid with a second fluid, to provide the second fluid to the subterranean formation, and/or to pump one or more structures into the wellbore. As illustrative, non-exclusive examples, this may include circulating a drilling fluid, such as a drilling mud, which may include sediment and/or particulate materials, from the wellbore, circulating a completion and/or breaker fluid into the subterranean formation, and/or to pumping a wiper plug to a terminal depth of the wellbore.

When valves 322 are in the blocking configuration, casing strings 240 and/or casing conduit 244 thereof may define a fluid-tight, or at least substantially fluid-tight, fluid conduit that extends between surface region 260 and a terminal end 254 of the casing string. As such, all, or at least a majority, of a fluid that may be provided to the casing conduit at and/or near surface region 260 (such as via a wellhead 222) may flow within casing conduit 244 to terminal end 254 before entering the subterranean formation. This may permit performing the above-described operations and/or processes efficiently and/or performing the above-described operations and/or processes without the need for installation of an inner string within casing conduit 244, which may decrease the time and/or costs associated therewith.

As an illustrative, non-exclusive example, the circulating may be accomplished by providing a circulating fluid from surface region 260 and/or wellhead 222 to one of casing conduit 244 and an annular space 232, which extends between casing string 240 and wellbore 230, flowing the circulating fluid to terminal end 254 of the casing conduit, and returning the circulating fluid to the surface region and/or the wellhead through the other of casing conduit 244 and annular space 232. As discussed, the drilling fluid may be circulated from wellbore 230 prior to occurrence of the flow-initiation event. Thus, a substantial portion, a majority, or all of the circulating fluid may be transferred between casing conduit 244 and annular space 232 at terminal end 254 and little and/or none of the circulating fluid may flow through valves 322 of contoured bosses 300.

As another illustrative, non-exclusive example, it may be desirable to stimulate subterranean formation 268 by flowing a stimulant fluid through valves 322 of contoured bosses 300 and into the subterranean formation. Under these conditions, valves 322 may define a stimulation flow path to convey fluid outflow, and are configured to permit fluid outflow and resist fluid inflow.

It is within the scope of the present disclosure that all, or substantially all, through valves 322 that are associated with all, or substantially all, contoured bosses 300 present within well 220 may be used for the stimulation of the subterranean formation. However, it is also within the scope of the present disclosure that, as indicated in dash-dot lines in FIG. 7, valves 322 of contoured bosses 300 may be arranged in a plurality of zones 290 of casing conduit 244 (with a first zone 292, a second zone 294, and a third zone 296 being illustrated therein), which may be configured to selectively transition to a flow configuration responsive to different flow-initiation events (such as a first flow-initiation event, a second flow-initiation event, and a third flow-initiation event, respectively). Similarly, subterranean formation 268 may include and/or define a plurality of regions 270 (with a first region 272, a second region 274, and a third region 276 being illustrated therein), which may be stimulated separately and/or independently from one another via valves 322 of contoured bosses 300 that are associated with first zone 292, second zone 294, and/or third zone 296, respectively.

One method for stimulating a plurality of zones 290 is to employ check valves 322 having different pressure set points in different zones. For example, a set of check valves 322 having the lowest pressure set points may be utilized in first zone 292 to stimulate first region 272. A set of check valves 322 having somewhat higher pressure set points may be utilized in second zone 294 to stimulate second region 274, while a set of check valves 322 having still higher pressure set points may be utilized in third zone 296 to stimulate third region 276. The stimulating fluid may be supplied at pressures sufficient to open certain check valves but not others, to separately stimulate desired regions, with the optional use of suitable plugs, or the like, employed to facilitate the process. Conversely, multiple regions may be stimulated simultaneously, with the check valves 322 having lower set points, set to account for the pressure drop across the casing system.

As may be appreciated by those skilled in the art, the systems and methods described in International Patent Application Publication Number WO 2012/087431, filed on Nov. 2, 2011, the contents of which are hereby incorporated by reference in their entirety, may be employed to separately stimulate first region 272, second region 274 and/or third region 276. These methods may be repeated any suitable number of times to stimulate any suitable number of regions 70 of the subterranean formation, such as at least 2, at least 4, at least 6, at least 8, at least 10, at least 15, at least 20, at least 25, at least 30, at least 40, or at least 50 regions of the subterranean formation.

A wide variety of check valves have utility in the systems and methods disclosed herein. One such check valve is the C200 Series cartridge check valve, available from Circle Seal Controls of Corona, Calif. To provide sufficient flow for a stimulation operation, check valves 322 may be provided with an orifice of a certain dimension suitable for its purpose. As used herein, the orifice may include and/or define any suitable orifice characteristic dimension, such as a characteristic orifice diameter. As illustrative, non-exclusive examples, the orifice characteristic dimension may be at least 6 millimeters (mm), at least 8 mm, at least 10 mm, at least 12 mm, at least 14 mm, at least 16 mm, at least 18 mm, at least 20 mm, at least 22 mm, or at least 24 mm. As another illustrative, non-exclusive example, the stimulation orifice characteristic dimension may be less than 40 mm, less than 38 mm, less than 36 mm, less than 34 mm, less than 32 mm, less than 30 mm, less than 28 mm, less than 26 mm, less than 24 mm, less than 22 mm, less than 20 mm, less than 18 mm, or less than 16 mm.

As used herein, the phrase “characteristic dimension” may refer to any suitable average, representative, and/or effective dimension. Thus, the characteristic dimension may, additionally or alternatively, be referred to herein as a diameter, an effective diameter, a characteristic diameter, an extent, a maximum extent, and/or a minimum extent.

As an illustrative, non-exclusive example, and when the orifice is a circular stimulation orifice, the stimulation orifice characteristic dimension may be defined by the diameter of the circular stimulation orifice. As another illustrative, non-exclusive example, and when the orifice is not a circular orifice, the orifice characteristic dimension may be defined by a maximum extent of the orifice, a minimum extent of the orifice, and/or by a diameter of a circle that defines a cross-sectional area that is the same as that of the stimulation orifice (i.e., an effective diameter of the orifice).

As used herein, the phrase “flow-initiation event” may include any suitable event, condition, and/or phenomenon that may occur and/or be generated within hydrocarbon well 220. As an illustrative, non-exclusive example, the flow-initiation event may include, or be associated with, generating a pressure differential between the casing conduit and the subterranean formation that is greater than a threshold pressure differential (i.e., a condition in which a pressure within casing conduit 244 and in the vicinity of a valve 322 is greater than a pressure within subterranean formation 268 and in the vicinity of a valve 322 by at least a threshold magnitude). This threshold pressure differential also may be referred to herein as a threshold positive pressure differential, a set point pressure or a cracking pressure. As illustrative, non-exclusive examples, the threshold positive pressure differential, set point pressure or cracking pressure of valves 322 may be set to fall within a range of at least 0.1 psig to 25 psig, and may be greater than 0.5 psig, greater than 1 psig, greater than 5 psig, greater than 10 psig, great than 15 psig, greater than 20 psig or greater than 25 psig, as required by the operation to be employed.

As indicated, it is within the scope of the present disclosure that a plurality of contoured bosses 300 having valves 322 be employed. It is further within the scope of the present disclosure that each of the valves 322 that are present within the wellbore may be designed, constructed, and/or configured to transition to a flow configuration responsive to the same, or at least substantially the same, flow-initiation event. However, it is also within the scope of the present disclosure that at least a first portion of valves 322 may be designed, constructed, and/or configured to transition to a flow configuration responsive to a first flow-initiation event, that at least a second portion of the valves 322 may be designed, constructed, and/or configured to transition to a flow configuration responsive to a second flow-initiation event, and that the first flow-initiation event may be different from, or have a different magnitude than, the second flow-initiation event. As an illustrative, non-exclusive example, the first portion of the valves 322 may be configured to transition the flow configuration at a first pressure differential, and the second portion of the valves 322 may be configured to transition to the flow configuration at a second pressure differential that is different from, or greater than, the first pressure differential.

It is within the scope of the present disclosure that the aforementioned transitioning may be based, at least in part, on any suitable criteria. As an illustrative, non-exclusive example, the transitioning may be responsive, or directly responsive, to the generating, directly responsive to the pressure within the casing conduit, and/or directly responsive to the pressure differential. This may include transitioning without mechanically actuating the wellbore flow-control device and/or without transmitting a control signal, such as a wireless control signal, a radio control signal, and/or an electronic control signal, to the wellbore flow-control device.

Stimulating the subterranean formation may include providing, conveying, and/or flowing a stimulant fluid, such as a fracturing fluid, a proppant, and/or an acid, from the casing conduit and into the subterranean formation.

The contoured bosses disclosed herein are capable of providing other utilities. In this regard, in yet another aspect, provided is a method of centering a tubular member having an outer surface within a borehole. The method includes the steps of: (a) establishing a first distance along the tubular member; and (b) welding a plurality of contoured bosses to the outer surface of the tubular casing at the first distance, each contoured boss including a mounting surface for contacting the outer surface of the tubular casing, the mounting surface having an outer periphery; and a contoured outer surface that extends radially outward from an outer surface of the tubular member, the contoured outer surface rounded to reduce surface contact with the borehole surface when the tubular member is positioned within the borehole; wherein the plurality of contoured bosses are positioned at equal distances about the circumference of the tubular member.

In some embodiments, the method further includes the steps of: (c) establishing a second distance along the tubular member; and (d) welding a plurality of contoured bosses to the outer surface of the tubular casing at the second distance, each contoured boss including a mounting surface for contacting the outer surface of the tubular casing, the mounting surface having an outer periphery; and a contoured outer surface that extends radially outward from an outer surface of the tubular member, the contoured outer surface rounded to reduce surface contact with the borehole surface when the tubular member is positioned within the borehole; wherein the plurality of contoured bosses are positioned at equal distances about the circumference of the tubular member.

In some embodiments, the method further includes the steps of: (e) establishing a third distance along the tubular member; and (f) welding a plurality of contoured bosses to the outer surface of the tubular casing at the third distance, each contoured boss including a mounting surface for contacting the outer surface of the tubular casing, the mounting surface having an outer periphery; and a contoured outer surface that extends radially outward from an outer surface of the tubular member, the contoured outer surface rounded to reduce surface contact with the borehole surface when the tubular member is positioned within the borehole; wherein the plurality of contoured bosses are positioned at equal distances about the circumference of the tubular member.

The method of centering a tubular member within a borehole, disclosed herein, possesses advantages over other known methods. For example, as those skilled in the art will recognize, bands are sometimes positioned at intervals along a tubular member for centering purposes. Such a band, having a uniform circumferential surface, and frequently little clearance between itself and the borehole, does not provide a bypass passage for material to travel past the band. As may be appreciated, this can cause binding of the tubular member during installation. Referring to FIGS. 1 and 6, it may be seen that substantial bypass passages may be provided.

As disclosed in more detail hereinabove, each contoured boss may include a valve receiving body having an axial bore for receiving a valve, the axial bore extending through the valve receiving body, the axial bore of the contoured boss in fluid communication with the interior of the tubular member.

In the present disclosure, several of the illustrative, non-exclusive examples have been discussed and/or presented in the context of flow diagrams, or flow charts, in which the methods are shown and described as a series of blocks, or steps. Unless specifically set forth in the accompanying description, it is within the scope of the present disclosure that the order of the blocks may vary from the illustrated order in the flow diagram, including with two or more of the blocks (or steps) occurring in a different order and/or concurrently. It is also within the scope of the present disclosure that the blocks, or steps, may be implemented as logic, which also may be described as implementing the blocks, or steps, as logics. In some applications, the blocks, or steps, may represent expressions and/or actions to be performed by functionally equivalent circuits or other logic devices. The illustrated blocks may, but are not required to, represent executable instructions that cause a computer, processor, and/or other logic device to respond, to perform an action, to change states, to generate an output or display, and/or to make decisions.

As used herein, the term “and/or” placed between a first entity and a second entity means one of (1) the first entity, (2) the second entity, and (3) the first entity and the second entity. Multiple entities listed with “and/or” should be construed in the same manner, i.e., “one or more” of the entities so conjoined. Other entities may optionally be present other than the entities specifically identified by the “and/or” clause, whether related or unrelated to those entities specifically identified. Thus, as a non-limiting example, a reference to “A and/or B,” when used in conjunction with open-ended language such as “comprising” may refer, in one embodiment, to A only (optionally including entities other than B); in another embodiment, to B only (optionally including entities other than A); in yet another embodiment, to both A and B (optionally including other entities). These entities may refer to elements, actions, structures, steps, operations, values, and the like.

As used herein, the phrase “at least one,” in reference to a list of one or more entities should be understood to mean at least one entity selected from any one or more of the entity in the list of entities, but not necessarily including at least one of each and every entity specifically listed within the list of entities and not excluding any combinations of entities in the list of entities. This definition also allows that entities may optionally be present other than the entities specifically identified within the list of entities to which the phrase “at least one” refers, whether related or unrelated to those entities specifically identified. Thus, as a non-limiting example, “at least one of A and B” (or, equivalently, “at least one of A or B,” or, equivalently “at least one of A and/or B”) may refer, in one embodiment, to at least one, optionally including more than one, A, with no B present (and optionally including entities other than B); in another embodiment, to at least one, optionally including more than one, B, with no A present (and optionally including entities other than A); in yet another embodiment, to at least one, optionally including more than one, A, and at least one, optionally including more than one, B (and optionally including other entities). In other words, the phrases “at least one,” “one or more,” and “and/or” are open-ended expressions that are both conjunctive and disjunctive in operation. For example, each of the expressions “at least one of A, B and C,” “at least one of A, B, or C,” “one or more of A, B, and C,” “one or more of A, B, or C” and “A, B, and/or C” may mean A alone, B alone, C alone, A and B together, A and C together, B and C together, A, B and C together, and optionally any of the above in combination with at least one other entity.

In the event that any patents, patent applications, or other references are incorporated by reference herein and define a term in a manner or are otherwise inconsistent with either the non-incorporated portion of the present disclosure or with any of the other incorporated references, the non-incorporated portion of the present disclosure shall control, and the term or incorporated disclosure therein shall only control with respect to the reference in which the term is defined and/or the incorporated disclosure was originally present.

As used herein the terms “adapted” and “configured” mean that the element, component, or other subject matter is designed and/or intended to perform a given function. Thus, the use of the terms “adapted” and “configured” should not be construed to mean that a given element, component, or other subject matter is simply “capable of” performing a given function but that the element, component, and/or other subject matter is specifically selected, created, implemented, utilized, programmed, and/or designed for the purpose of performing the function. It is also within the scope of the present disclosure that elements, components, and/or other recited subject matter that is recited as being adapted to perform a particular function may additionally or alternatively be described as being configured to perform that function, and vice versa.

INDUSTRIAL APPLICABILITY

The systems and methods disclosed herein are applicable to the oil and gas industry.

It is believed that the disclosure set forth above encompasses multiple distinct inventions with independent utility. While each of these inventions has been disclosed in its preferred form, the specific embodiments thereof as disclosed and illustrated herein are not to be considered in a limiting sense as numerous variations are possible. The subject matter of the inventions includes all novel and non-obvious combinations and subcombinations of the various elements, features, functions and/or properties disclosed herein. Similarly, where the claims recite “a” or “a first” element or the equivalent thereof, such claims should be understood to include incorporation of one or more such elements, neither requiring nor excluding two or more such elements.

It is believed that the following claims particularly point out certain combinations and subcombinations that are directed to one of the disclosed inventions and are novel and non-obvious. Inventions embodied in other combinations and subcombinations of features, functions, elements and/or properties may be claimed through amendment of the present claims or presentation of new claims in this or a related application. Such amended or new claims, whether they are directed to a different invention or directed to the same invention, whether different, broader, narrower, or equal in scope to the original claims, are also regarded as included within the subject matter of the inventions of the present disclosure. 

1. A contoured boss for conforming to an outer surface of a tubular member for deployment within a subterranean formation, said contoured boss comprising a valve receiving body having a contoured outer surface that extends radially outward from an outer surface of the tubular member; and a passage for receiving a valve, said passage extending through said valve receiving body.
 2. The contoured boss of claim 1, wherein the contoured outer surface of the valve receiving body is rounded to reduce surface contact with a borehole surface when the tubular member is positioned within the borehole of the subterranean formation.
 3. The contoured boss of claim 2, wherein said valve receiving body includes a mounting surface for contacting the outer surface of the tubular member, said mounting surface having an outer periphery.
 4. The contoured boss of claim 3, wherein said contoured outer surface of said valve receiving body has an outer periphery, said outer periphery of said contoured outer surface located adjacent said outer periphery of said mounting surface of said valve receiving body.
 5. The contoured boss of claim 4, wherein said valve receiving body further comprises a welding chamfer, said welding chamfer positioned between said outer periphery of said contoured outer surface and said outer periphery of said mounting surface.
 6. The contoured boss of claim 4, wherein said contoured outer surface of said valve receiving body is substantially dome-shaped, tear-drop shaped, or rib-shaped.
 7. The contoured boss of claim 6, wherein said passage of said valve receiving body comprises an axial bore having a first portion having a first diameter, said first diameter sufficient to receive the valve from said contoured outer surface, said first portion of said axial bore extending partially through said valve receiving body and terminating at a valve seating shoulder.
 8. The contoured boss of claim 7, wherein said axial bore of said passage has a second portion having a second diameter, said second diameter less than said first diameter, said second portion of said axial bore initiating at said valve seating shoulder and extending through said mounting surface.
 9. The contoured boss of claim 8, wherein said axial bore of said passage includes an annular groove for receiving a lock ring for securing the valve within said axial bore.
 10. The contoured boss of claim 9, further comprising a lock ring positionable within said annular groove for securing the valve within said axial bore.
 11. The contoured boss of claim 9, further comprising a screen for preventing debris from entering the valve, said screen retained within said axial bore by said lock ring.
 12. The contoured boss of claim 3, wherein said mounting surface for contacting the outer surface of the tubular member is contoured to substantially mate with the outer surface of the tubular member.
 13. A method for facilitating stimulation treatments in completions, the method comprising the steps of: (a) drilling a hole through a tubular casing at a first distance along the tubular casing; (b) welding a contoured boss to an outer surface of the tubular casing, the contoured boss comprising a valve receiving body; a contoured outer surface that extends radially outward from an outer surface of a tubular casing; and a passage for receiving the valve, the passage extending through the valve receiving body and in fluid communication with the hole of the casing; and (c) positioning a valve within the passage.
 14. The method of claim 13, wherein the contoured outer surface of the valve receiving body is rounded to reduce surface contact with a borehole surface when the tubular casing is positioned within the borehole of the subterranean formation.
 15. The method of claim 14, wherein the valve receiving body includes a mounting surface for contacting the outer surface of the tubular casing, the mounting surface having an outer periphery.
 16. The method of claim 15, wherein the contoured outer surface of the valve receiving body has an outer periphery, the outer periphery of the contoured outer surface located adjacent the outer periphery of the mounting surface of the valve receiving body.
 17. The method of claim 16, wherein the valve receiving body further comprises a welding chamfer, the welding chamfer positioned between the outer periphery of the contoured outer surface and the outer periphery of the mounting surface.
 18. The method of claim 17, wherein the contoured outer surface of the valve receiving body is substantially dome-shaped, tear-drop shaped, or rib-shaped.
 19. The method of claim 18, wherein said passage of the valve receiving body comprises an axial bore having a first portion having a first diameter, the first diameter sufficient to receive the valve from the contoured outer surface, the first portion of the axial bore extending partially through the valve receiving body and terminating at a valve seating shoulder.
 20. The method of claim 19, wherein the axial bore of the passage has a second portion having a second diameter, the second diameter less than the first diameter, the second portion of the axial bore initiating at the valve seating shoulder and extending through the mounting surface.
 21. The method of claim 20, wherein the axial bore of the passage includes an annular groove for receiving a lock ring for securing the valve within the axial bore.
 22. The method of claim 21, further comprising installing a lock ring within the annular groove to secure the valve within the axial bore.
 23. The method of claim 21, further comprising installing a screen for preventing debris from entering the valve; and installing a lock ring within the annular groove to secure the valve and screen within the axial bore.
 24. The method of claim 13, further comprising the step of: (d) repeating steps (a)-(c).
 25. The method of claim 13, further comprising the step of: (d) twice repeating steps (a)-(c), wherein three valves are positioned at equal distances about the circumference of the tubular casing to establish a first treatment zone.
 26. The method of claim 13, wherein the contoured boss does not restrict tubular flow.
 27. The method of claim 26, further comprising the steps of: (e) drilling a hole through a tubular casing at a second distance along the tubular casing, the second distance greater than the first distance; (f) welding a contoured boss to an outer surface of the tubular casing, the contoured boss comprising a valve receiving body; a contoured outer surface that extends radially outward from an outer surface of the tubular casing; and a passage for receiving the valve, the passage extending through the valve receiving body and in fluid communication with the hole of the casing; and (g) positioning a valve within the axial bore.
 28. The method of claim 27, further comprising the step of: (h) thrice repeating steps (a)-(c), wherein four valves are positioned at equal distances about the circumference of the tubular casing to establish a second treatment zone.
 29. The method of claim 28, wherein the valves are check valves.
 30. The method of claim 29, wherein the check valves installed at the first distance of the tubular casing require a lower pressure to open than those installed at the second distance of the tubular casing.
 31. A method of centering a tubular member having an outer surface within a borehole, the method comprising the steps of: (a) establishing a first distance along the tubular member; and (b) welding a plurality of contoured bosses to the outer surface of the tubular casing at the first distance, each contoured boss comprising a mounting surface for contacting the outer surface of the tubular casing, the mounting surface having an outer periphery; and a contoured outer surface that extends radially outward from an outer surface of the tubular member, the contoured outer surface rounded to reduce surface contact with the borehole surface when the tubular member is positioned within the borehole; wherein the plurality of contoured bosses are positioned at equal distances about the circumference of the tubular member.
 32. The method of claim 31, further comprising the steps of: (c) establishing a second distance along the tubular member; and (d) welding a plurality of contoured bosses to the outer surface of the tubular casing at the second distance, each contoured boss comprising a mounting surface for contacting the outer surface of the tubular casing, the mounting surface having an outer periphery; and a contoured outer surface that extends radially outward from an outer surface of the tubular member, the contoured outer surface rounded to reduce surface contact with the borehole surface when the tubular member is positioned within the borehole; wherein the plurality of contoured bosses are positioned at equal distances about the circumference of the tubular member.
 33. The method of claim 32, further comprising the steps of: (e) establishing a third distance along the tubular member; and (f) welding a plurality of contoured bosses to the outer surface of the tubular casing at the third distance, each contoured boss comprising a mounting surface for contacting the outer surface of the tubular casing, the mounting surface having an outer periphery; and a contoured outer surface that extends radially outward from an outer surface of the tubular member, the contoured outer surface rounded to reduce surface contact with the borehole surface when the tubular member is positioned within the borehole; wherein the plurality of contoured bosses are positioned at equal distances about the circumference of the tubular member.
 34. The method of claim 33, wherein each contoured boss further comprises a valve receiving body having an axial bore for receiving a valve, the axial bore extending through the valve receiving body, the axial bore of the contoured boss in fluid communication with the interior of the tubular member.
 35. A collar or sub for mounting to a tubular member for deployment within a subterranean formation, said collar or sub comprising a plurality of contoured bosses integrally formed thereon and spaced about an outer surface thereof, each of said contoured bosses comprising a valve receiving body having a contoured outer surface that extends radially outward from an outer surface of the tubular member; and a passage for receiving a valve, said passage extending through said valve receiving body.
 36. The collar or sub of claim 35, wherein the contoured outer surface of the valve receiving body is rounded to reduce surface contact with a borehole surface when the tubular member is positioned within the borehole of the subterranean formation.
 37. The collar or sub of claim 36, wherein said contoured outer surface of said valve receiving body is substantially dome-shaped, tear-drop shaped, or rib-shaped.
 38. The collar or sub of claim 37, wherein said passage of said valve receiving body comprises an axial bore having a first portion having a first diameter, said first diameter sufficient to receive the valve from said contoured outer surface, said first portion of said axial bore extending partially through said valve receiving body and terminating at a valve seating shoulder.
 39. The collar or sub of claim 38, wherein said axial bore of said passage has a second portion having a second diameter, said second diameter less than said first diameter, said second portion of said axial bore initiating at said valve seating shoulder and extending through said mounting surface.
 40. The collar or sub of claim 39, wherein said axial bore of said passage includes an annular groove for receiving a lock ring for securing the valve within said axial bore.
 41. The collar or sub of claim 40, further comprising a lock ring positionable within said annular groove for securing the valve within said axial bore.
 42. The collar or sub of claim 40, further comprising a screen for preventing debris from entering the valve, said screen retained within said axial bore by said lock ring. 